1. Field of the Invention
This invention relates in general to operations in oil and gas wells, and in particular to completion operations with a ball launcher for successively launching an indefinite number balls into a wellbore while mounted on a wellhead assembly.
2. Description of Related Art
Balls are sometimes launched into a wellbore promote oil and gas flow from a hydrocarbon producing wellbore. Reasons for injecting the balls including using a ball as a sealing member by having the ball land on a seat formed on an end of a tubular, where the inner diameter of the tubular is less than the outer diameter of the ball. In other applications, balls may be forced with pressure through a tubular for cleaning the tubular (similar to a pigging operation) or otherwise removing debris or obstructions within the tubular. Balls may be mixed with a treating fluid that is injected into an adjoining formation that produces oil and gas. Additional examples include landing the ball in a segment of casing to divert a flow of cement during staging operations. Balls dropped within a wellbore are also used to activate tools downhole, such as by shearing a pin or directly contacting a switch or other device for activating a tool. From time to time the ball may be used to operate as a safety valve. Typically, as the wellbore is generally at a pressure greater than ambient pressure at the surface, the balls are held for a period of time within a pressurized environment prior to being dropped into the wellbore.